Japanese Patent No. 4894572 discloses an apparatus that determines a reference face direction which is a face direction when a driver faces frontward while driving a vehicle. The apparatus determines the reference face direction as an direction which a driver faces toward for a long time, based on a face direction of a driver when a vehicle travels forward, a change in the face direction of the driver is within a predetermined range, and a steering angle of a steering wheel of the vehicle is within a predetermined range.